when dota 2 got announced, pendragon or one of the other old dota developers who went to riot copyrighted DotA and defense of the ancients.
they then gave this to Blizzard (probably hoping Blizzard would use their legal power to shut them down).

this is why Valve only call it Dota (no capital A) and never ever reference it as defense of the ancients.
theres alot of shit flung in the background but Blizzard copped ALOT of bad press last time they challenged valve over this issue, i seriously doubt they will do it again.

copyright/trademark still stands. you can't really copyright similar apperance. but hero names have been changed, centaur warchief is centaur warrunner. obsidian destroyer is called outworld destroyer. it's enough that they can't be sued.

you could use a behavior with a search effect that triggers a set effect (that does nothing) on the source unit. you could then have an effect used event. i use null type effects alot of set off triggers.

more than likely have a thread that runs either in a infinite loop or every second or less. depending on performance or whatever, either a thread for each lurker or one thread that loops through all the lurkers and checks number of enemy units in circle with radius of 6. if > 0 then burrow.

mine isn't working but for a different reason
seems you can't launch the editor anymore without a hots key anymore.
which fucks me over. i was porting SC2BW to hots to prepare. now i can't even launch the editor.

particles are a huge pain right now.
everytime i think i've got them worked out. they work completely different. it's a nightmare. theres way too many values in there that we have no information about.

i'd say yea. wait. the easiest way is probably have good attachment points on your models and use already existing launch effect actors.